Breathability and Protection Aspects of Moisture Barriers Used in Fire Fighters Protective Clothing After Thermal Aging

The effect of heat on the water vapor permeability and the watertightness of different breathable fabrics has been analysed. Samples have been exposed to a radiant heat source or were put in an oven for definite times with assessment of the changes in their waterproof and breathable properties. This study shows that microscopic changes in the structure of several materials occur after very short exposures to heat which cause a reduction in the breathability of most materials. The waterproof properties, however, remain unchanged as long as no visible damage has occurred. The microscopic changes in the structure can lead to a decrease of the breathability of heat exposed samples of more than 30%.